Buggy code:
public class ResultsBuilder { private static final Logger logger = LoggerFactory . getLogger ( ResultsBuilder . class ) ; public static final String RESULT = "results.csv" ; public static final String RESULT_REQS = "requests.csv" ; public static final String RESULT_WORKLOAD = "workload.csv" ; public static final String RESULT_RES_TIMES = "responseTimes.csv" ; public static void main ( String [ ] args ) { } private static Map < String , List < Double > > getAsMap ( Path f , String [ ] ss ) { } public static final String JMETER_LOG = "test_aggregate.jtl" ; private static Map < String , Integer > getRequestsPerPage ( Path parent , boolean onlyOk ) throws Exception { } private static Map < String , Integer > getRequestsPerPageFromSingleFile ( Path f , boolean onlyOk ) throws Exception { } private static Map < String , String > getLatenciesPerPage ( Path parent , boolean onlyOk ) throws Exception { } private static Map < String , String > getLatenciesPerPageFromSingleFile ( Path f , boolean onlyOk ) throws Exception { } public static final String DEMAND_COLUMN_PREFIX = "AvarageEstimatedDemand_" ; public static final String CPU_UTIL_COLUMN = "AvarageCPUUtil" ; public static final String WORKLOAD_COLUMN = "workload" ; public static final int TIME_SLOT_SIZE = 5 * 60 ; private static DecimalFormat doubleFormatter ( ) { DecimalFormatSymbols otherSymbols = new DecimalFormatSymbols ( Locale . getDefault ( ) ) ; otherSymbols . setDecimalSeparator ( '.' ) ; <START_BUG> DecimalFormat myFormatter = new DecimalFormat ( "0.000" , otherSymbols ) ; <END_BUG> return myFormatter ; } private static DecimalFormat doubleFormatter = ResultsBuilder . doubleFormatter ( ) ; public static void perform ( Path parent , String [ ] methodsNames , int cores ) { } private static List < List < Double > > methodsWorkloads = null ; private static Map < Integer , Integer > methodsWorkloadTot = null ; private static Map < String , List < Double > > demands = null ; private static int maxCommonLength = - 1 ; private static void init ( Path parent , String [ ] methodsNames ) { } public static void createDemandAnalysis ( Path parent , String [ ] methodsNames , int cores ) { } public static void createRequestsAnalysis ( Path parent , String [ ] methodsNames , int window , boolean printOnlyTotalRequests ) { } public static void createWorkloadAnalysis ( Path parent , String [ ] methodsNames , int timesteps ) { } public static void createResponseTimesAnalysis ( Path parent , String [ ] methodsNames ) { } private static Map < String , String > getLatenciesPerPageFromGlassfish ( Path parent , String [ ] methodsNames ) throws Exception { } private static String parseGlassfishJson ( Path jsonFile ) throws Exception { } private static Map < String , String > getResponseTimesPerPageFromDataCollector ( Path parent , String [ ] methodsNames ) throws Exception { } private static Map . Entry < String , String > getResponseTimesPerPageFromSingleFile ( Path p ) throws Exception { } public static final int DEFAULT_TIMESTEPS = 5 ; public static void perform ( Path parent , String [ ] methodsNames , int window , boolean printOnlyTotalRequests , int cores ) { } }

Fix:
DecimalFormat myFormatter = new DecimalFormat ( "0.0#########" , otherSymbols ) ;